Title :
Capacity of DS/CDMA communication systems with optimum spectral overlap
Author :
Han, Jin Hee ; Kim, Sang Wu
Author_Institution :
Dept. of Electr. Eng., Korea Adv. Inst. of Sci. & Technol., Taejon, South Korea
Abstract :
We consider frequency overlapped DS/CDMA (FO/CDMA) communication systems where a number of DS/CDMA systems share frequency bands with adjacent systems. We analyze the multiple-access interference from adjacent systems with arbitrary amount of frequency overlap and compare the capacity of FO/CDMA with that of single wideband CDMA (WCDMA). The optimum amount of overlap increases with the number of overlapped systems. However the maximum capacity is obtained when the optimum number of systems are overlapped by half null-to-null bandwidth. It is shown that the FO/CDMA yields higher capacity in the case of relaxed bit error rate requirement and low decay rate of multipath intensity profile. Otherwise, WCDMA is superior.
Keywords :
Rayleigh channels; adjacent channel interference; channel capacity; code division multiple access; error statistics; multipath channels; spread spectrum communication; DS-CDMA communication system; Rayleigh fading channel; frequency overlap; half null-to-null bandwidth; low decay rate; multipath intensity profile; multiple-access interference; optimum spectral overlap; relaxed bit error rate requirement; system capacity; wideband CDMA; AWGN; Bandwidth; Delay; Fading; Frequency; Interference; Multiaccess communication; Signal resolution; Signal to noise ratio; Wideband;
Journal_Title :
Communications Letters, IEEE
DOI :
10.1109/4234.730371
